One of the key problems in constructing and maintaining communications systems is the limited scope of available transmission resources. This applies to communication systems utilizing wireless connections, in particular. In a wireless communication system, the usage of radio spectrum must be planned in detail. Careful planning of the use of radio frequencies aims at utilizing the available frequencies as efficiently as possible but simultaneously at minimizing co-channel interference and adjacent channel interference. By means of various models, available frequencies are divided into different cells so as to minimize the interference occurring in radio connections and thus maximize the network capacity. In a cell repeat pattern, the same or adjacent frequencies must not be too close to one another, because this causes excessive interference in the system.
On the other hand, a tight frequency reuse pattern is attractive because of the efficient usage of the frequencies. Solutions with a tight frequency reuse have been proposed for future wireless communications systems. In order to reduce co-channel interference and inter-cell interference, transmission level controlled by a power sequence may be applied to a base station. Adjacent base stations may use different power sequences to avoid instant over lapping in coverage.
The efficient use of power sequences requires that base stations be synchronized. The accuracy of synchronization of power sequences among adjacent base stations and delay variations of co-channel interferences from nearby base stations will affect the signal quality at receiving user equipment during power-level transitions. Errors in synchronization may cause situations where adjacent base stations transmit with a high power level using frequencies that are near each other or even the same. In such a case, the interference level at the receiving user equipment is very high. During the period of high interference, the symbols contained in the received signal may be lost.